Refrigerating apparatus



Oct. 25, 1938. G. c. PEARCE REFRIGERATING APPARATUS Original Filed Dec. 50, 1933 5 Sheets-Sheet 1 INVENTOR.

ATTORNEYS Oct. 25, 1938. c, PEARCE 2,134,056

REFRIGERATING APPARATUS Original Filed Dec. 50, 1933 5 Sheets-Sheet 2 GD g db ATTORNEYS Oct. 25, 1938. e. c. PEARCE REFRIGERATING APPARATUS Original Filed Dec. 50, 1953 5 Sheets-Sheet 5 /;VENTOR.

4% ATTORNEYS Oct. 25, 1938. c PEARCE REFRIGERATING' APPARATUS 5 Sheets-Sheet 4 Original Filed Dec. 30, 1933 0 2 O I M mi 0 3 5 I 5: 0 O 9 I 5 a My MM 13 0/1, i Ill/J V INVENTOR; 4W

ATTORNEYS Oct. 25, c PEARCE.

REFRIGERATING APPARATUS Original Filed Dec. 30, 1933 5 Sheets-Sheet 5 6 IN V NTOR.

w $4 ATTORNEYS Patented Oct. 25, 1938 UNITED STATES PATENT OFFICE 2,134,056 REFBIGERATING APPARATUS George C. Pearce, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware 13 Claims.

This invention relates to refrigerating apparatus and more particularly to control means therefor.

This application is a division of my copending application entitled Refrigerating apparatus, Serial No. 704,685, filed December 30, 1933.

It is an object of my invention to provide for refrigerating apparatus and other means an im-- proved switch having great flexibility as to range and differential adjustments and which will be equally applicable for use with alternating and direct current so that it may be easily and readily adjusted to fill the requirements of a wide range of situations.

It is another object of my invention to provide a switch means having an improved readily removable bellows assembly provided with protective means for preventing undue expansion of the bellows when removed from the remainder of the switch means and which serves as a useful part when connected to the remainder of the switch means.

It is a further object of my invention to provide an improved overload means for a magnet type switch having an improved resetting means which prevents the forcible closing of the circuit under overloading conditions. I

It is another object of my invention to provide an improved snap acting means for controlling the operation of a bellows and switch. means which will accommodate misalignment without being affected in its operation in any substantial way.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. l is a view of a refrigerating system including my improved control means;

Fig. 2 is a left side view of thepressure responsive in Fig.

Fig. 3 is a right side view of the pressure responsive assembly of the control means shown Fig. 4 is a side view of the overload means,

' also shown in Fig. 3, showing the overload means in resetting position;

Fig. 5 is a side view of the overload means in tripped position;

clomng the differential adjusting means;

assembly of the control means shown Fig. 7 is a sectional view along the line 7-1 of Fig. 6;

Fig. 8 is a fragmentary top view of the pressure responsive assembly including switch contacts and overload means; 5

Fig. 9 is a left side view of the high pressure cutout means shown in Fig. 1;

Fig. 10 is a right side view of the high pressure cutout means;

Fig. 11 is a sectional View along the line H-ll 10 of Fig. 1;

Fig. 12 is a sectional view along the line i2--i2 of Fig. 1;

Fig. 13 is a sectional view along the line "-13 of Fig. 11; and

Fig. 14 is a diagrammatic view of the switch mechanism laid out in such a manner as to illustrate the functions and operation of various parts of the mechanism.

Referring to the drawings and more particularly to Fig. 1, there is shown a refrigerant liquefying means including a compressor 20 driven by an electric motor 2| for compressing the refrigerant and for forwarding the compressed refrigerant to a condenser 22 where the refrigerant 25 is liquefied and collected in a receiver 23. From the receiver 23, the liquid refrigerant is forwarded through a supply conduit 24 to an evaporating means 25, which, as shown, may be of the low side float controlled flooded type or any 30 ductors II. The control means 30 is operated by a bellows 32 which is connected by tubing 33 to the return conduit 21. By this connection the bellows I2 is responsive to the pressure and therefore thetemperature of the evaporating means 25.

As better shown in Figs. 2 and3, the bellows 32 are located between two generally square, flat, upper and lower plates 14 and I5. At the opposite corners of the plates the plates are connected by pins I. which are provided with shoulders at their ends and a reduced portion which through the plates and is riveted over onto the opposite sides thereof so as to hold the plates in spaced relation.

As more particularly shown in Fig. 6, the bellows 32 is fastened to the lower plate 35 by having its bottom plate 31 seated upon the lower plate 35 and fastened thereto by means of the nut 38 which surrounds the upper end of the tube 33. The upper plate 34 serves as a stopto prevent undue expansion of the bellows under high pressure conditions within the system, such as are prevalent when thesystem is shut down. The upper plate 34 is provided with an aperture through which extends a pin 39 which is connected to the movable end of the bellows 32. This entire bellows assembly including the bellows 32, the tube 33, the upper and lower plates 34 and 35, aswell as the riveted pins 38 is fastened to a U-shaped bracket 48 by means of long machine screws 4!- which pass through the remaining two corners of both the upper and lower plates 34 and 35. i l

A pin 39 extending from the bellows assembly is provided with a conical point which projects into a recess provided in a bellows follower 42 which is provided with a pair of ears 43 at one end, which are pivoted upon a pivot pin 44,

' better shown in Fig. 7. This pivot pin 44 is supported by the pair of ears 45 projecting from the U-shaped bracket 48. The expansion of the bellows 32 is opposed by a spring adjusting means including a lower spring retainer 48 provided with a conical point 41 seated upon the bellows follower 42 substantially opposite the conical point of the pin 38 extending from the bellows assembly. Seated upon the spring retainer or spring seat 48 is a rather stifi heavy coil spring 49 which is concentric with an adjusting screw 48 having threaded thereon the upper spring retainer 58 which holds and confines the spring 49 between it and the lower spring retainer 48. The upper spring retainer is provided with a projection 5i which is guided by a slot in the upper end of the U-shaped bracket 48 in order to prevent the spring retainer 58 from turning when the screw 48 is turned. The tension of the spring 49 is adjusted by turning the-control knob 52 adjustably connected to a serrated disc 58 at the top of the screw 48. The knob 52 is preferably provided-with an arm 53 cooperating with a pin 51 to limit its normal rotation to one revolution in order to prevent any unauthorized person from adjusting the tension of the spring so as to pre-. vent the proper operation of the switch.- The knob 52 is provided with suitable. indicating means, such as shown at 54 in Fig. 2, to indicate the proper normal position of the control knob 52. The control knob 52 is'fastened to the screw 48 by a small threaded screw so that it isremovable together with arm 53 so that the service man -is permitted to turn a screw 48 to any amount he desires. The upper end of this screw 48 is upper end of the U-shaped bracket 48.

The bellows follower 42 at its free end is pivotally connected by a pin 242 to a link 88, which at its lower end is provided with a slot 8| slidably provided with a flange 55 which bears against the receiving a pin 82 which passes through and is slidably mounted within an arcuate slot 83 pro vided in an arm 283 extending from the U-shaped member 85. Thelocation of the pin 82 within the arcuate slot 83 is controlled by a long thin screw 84 extending in substantially the same direction as the arcuate slot 83 and which has an enlarged portion of the pin 82 threaded thereon. The screw 84- has its end rotatably and flexibly mounted within the U-shaped member 85 and is thus secured against longitudinal movement in the U-shaped member 85 to which the arm carrying the arcuate slot is fastened.

The location of the pin 82 within the arcuate slot 83 determines the differential of the switch by changing the distance of the pin 82 from the fulcrum pins 258 upon which the U-shaped member 85 pivots. In order to increase the difierential between the cut-in and cut-out points upon the switch the long thin screw 84 is turned so as to move the pin 82 inwardly closer to the pivot pins 258 upon which U-shaped pin 85 is pivoted. In order to decrease the differential the screw 84 is turned in the opposite direction'so as to move the pin 82 outwardly. The arm 283 having the arcuate slot 83 has its inner end rigidly fastened to the U-shaped member 85. A tension spring 58 connects the bellows follower and the end of the arm 283 having the arcuate slot 83 so as to normally hold the pin 82 in the inner end of the slot 81 in the link 88. However, should any resistance be encountered which is greater than the tension of the spring 58 the pins 82 will be permitted to, move away from the inner end of the slot 82 against the tension of the spring 58.

Connected to one' side of the U-shaped member 85 by rivets is an insulating strip 88 which carries an armature arm 81 of magnetic material fastened thereto by nut and' bolt means 88. It should be noted that there is provided a rigid assembly which includes the U-shaped member 85, the member 283, the insulating arm I88, the arm I54, the insulating strip 88, the armature arm 81, and the flexible contact member and which assembly pivots about the pivot pins 258 which pass through the U-shaped member 85 and the insulating members 15 and 95 which with the U-shaped member 48 form the nonmovable supporting frame of the switch. This nut and bolt means serves as a binding post to connect the electrical conductor 89 to the flexible contact member 18, preferably of spring brass, which is fastened to the top of the armature arm 81 by the nut and bolt means 88. This spring brass strip 18 is provided with a silver or silver plated contact 1| at its free end which projects through a necked in portion at the free end of the armature arm 81 and contacts with a cooperating'contact 13 which is located between the ends of a U-shaped permanent magnet 14. This U shaped permanent magnet 14 is mounted upon an insulating member 15 of hard rubber, or some suitable phenol condensation product. This insulating member 15 is provided with a flange 18 against which one side of the U-shaped magnet magnet 14 and which adjusts the minimum dis-' tance between the armature arm and the permanent magnet so as to pervent the armature arm from freezing to the permanent magnet.

The permanent magnet 14 sets up a magnetic field between the contacts and thus snuffs out any are which might pass between the contacts by the action of an electric turn in a magnetic field.v This is particularly valuable in connection with direct currents and enables the switch to have a relatively high direct current rating so that it may be used for both alternating and direct current. In addition to snufiing out the arc, the permanent magnet also aids in giving a snap movement to the armature arm. This also aids in preventing arcing at the contacts. With this arrangement, the differential between the cut-in and cut-out points may be made very small. The spring and slot link connection provided by the link 58, the slot 6|, the pin 62, and the spring 56 prevents any force greater than the tension of the spring 56 from being applied to the armature arm 61 so that any damage to the armature arm because of excessive expansion of the bellows 32 is avoided.

The stationary contact 13 is mounted upon an L-shaped brass or copper strip conductor 8| fastened to the top of the insulating member 15,

which member is provided with an ear 82 and a binding screw 88 for fastening the electrical conductor 84 thereto. The electrical conductor 68 which receives electrical energy from the conductor 84 through the L-shaped member, the stationary contact 13, the movable contact 1I, and the spring brass strip 18 is connected to a brass strip conductor 85 which has a turned up end portion 86 which limits the upward or outward movement of the armature arm 51. If desired, the armature arm 61 may be provided with a contact 81 which cooperates with a contact mounted upon the L-shaped member BI.

35 The brass strip conductor 85 is provided with an ear 88 at its opposite end to which is connected a coiled heater wire 88 which is connected by a binding post 88' to the electrical conductor 8| leading to the electrical motor 2i. Extending through the coiled portion of the heater wire 88 is an improved type of solder pct 82. This solder pct 82, as better shown in Fig. 8, has a hollow portion which is provided with a fusible material, such as a rather low melting solder 83. This solder melts and so absorbs a certain amount of heat by its change in state from the heater wire 88 before any further change in temperature of the solder pct 82 takes place. At the opposite end of the solder pot there is fastened a ratchet wheel by a slightly higher melting solder so that upon an overload suillciently high tocause the normal carrying capacity of the heater 88 to be exceeded the ratchet wheel will not be released until the special solder 83 is melted. This prevents actuation of the overload means under overloads over such a short period that no harm would be done to the apparatus. This solder pct 82 and heating coil 88 are mounted upon a second insulating member 85 which is parallel to the other insulating member 15 and which extends between the end portions of the .U-shaped bracket 48. f This second insulating member 85 carries the overload mechanism. The remaining mechanism of the overload mechanism is mounted at the side of the insulating member 85. This mechanism comprises a formed strip metal slide member 86 which is slidable upon the pins 81 directly beneath and behind an insulating actuating member 88 which is also to the left as viewed in Fig. 3 so that the spring catch 88 is urged in engagement with the teeth of the ratchet wheel 84 by a tension coil spring I82 which has one end connected to an ear I83 extending from the member 86 and the other end connected to a pin I84 extending from the insulating member 85. The member 86 on the opposite side is provided with a pivot pin I88 which extends through an intermediate portion of a floating lever I8I. One end of this lever I8I extends into a notch I85 formed in the member 88 and this forms the sole connection between the slide 85 and the member. 88, while the other end of the lever I85 extends in an opposite direction beneath an insulating arm I86 which extends from the U-shaped bracket 65 on a side opposite the insulating arm 66.

When an excessive amount of current flows 7 through the switch and particularly through the heater coil 88, the solder or fusible material 83 will first be melted and'then the solder connecting the ratchet wheel with the stem of the solder pot 82 will meltand permit rotation of the ratchet wheel. This will release the spring member 88 and the member 85 and permit the spring I82 to carry the member 85 and the lever I8I toward the left as viewed in Fig. 3, so that an end of the lever I8I will engage the end of the arm I86, as shown in Fig. 5, in order to forcibly move the armature arm 61 and the contact H to open circuit position. This movement is permitted regardless of the condition of the bellows 32 by reason of the slot 6| which under the control of the spring 56 permits the movement of the armature arm 61 independently of the movement of the bellows in this direction. This slot and spring connection of the slot and the spring 56 also prevents damage to the armature arm by taking up any excess movement and expansion of the bellows 32 without placing a force upon the armature arm greater than the tension of the spring 51.

In order to reset the overload means, the member 88 is forced directly downwardly as shown in Fig. 4 so that its notch I85 bears upon the one end of the lever I8I against the tension of the spring I81 and so that by the reaction of this force, the other end of the lever I8I- contacts with the arm I 86 and thereby holds the switch contacts open. The reaction of the force imposed upon the lever IN by the notch I85 alsomoves the slide member 86 downwardly against the tension of a spring I82 so that the spring catch 88 is moved beneath the ratchet wheel as viewed in Fig. 4 so that when the member 88 is released the spring catch will rise and engage the ratchet wheel and permit the lever I8l to move away from the arm I86 in order to permit the switch contacts to move to closed position. The member 88 may also be employed to open the. contacts by pressing directly down thereon to cause the lever IM to be turned in a clockwise direction as shown in Fig. 4 to engage the arm I86.

Referring now more particularly to Figs. 1 and 9 to 13 inclusive, there is provided a high pressure cutout mechanism at the left of the pressure responsive mechanism heretofore described. This high pressure cut-out mechanism isprovided with a U-shaped bracket I28 simliar to bracket 48 which has a bellows assembly mounted on one end. This bellows assembly has an upper plate I2I and a lower plate I22 riveted together by pins I26 similar to the other bellows assembly. Th bellows assembly is fastened to the U-shaped bracket I20 by screws I I9 which pass through opposite corners of the upper and lower plates I2I and I22. Fastened to the lower plate is the end plate I23 which carries the high pressure tubing I24 connecting the bellows assembly with the supply conduit 24. Surrounding the upper end of the tubing I24 is a gland nut I25 which fastens the end member I23 to the bottom plate I22. The high pressure tubing I24 is soldered to the end plate I23 to seal the connection.

Connected to the end plate I23 and sealed thereto, is a tubular member I21 which is connected at its'upper end to the upper end of a bellows I28 locatedwithin the cylindrical member I21. Within the bellows I28 is a pin I29 having a reduced portion I30 extending through the closed lower end of the bellows into the central passage within the end plate I23. The upper end of the pin I28 has a reduced portion I3I which extends through a central aperture in the upper plate I2I and an aperture in the U-shaped bracket I20 and has a conical point at its upper endwhich engages a recess in the bellows follower I32. The bellows follower is a triangular plate provided with a pair of ears I60 receiving a pivot pin I6I which is'held by a pair of ears I62 extending from the U-shaped bracket I20. This reduced portion I of the pin forms a shoulder which is adapted to engage the upper plate I2I in order to prevent the complete collapse of the bellows I28.

The movement of the bellows I28 and the pin I29 is controlled by resilient adjusting means including a lower spring retainer I33 having a coni-' cal point I34 which engages a recess in bellows follower I32 substantially directly opposite the pin I39. Seated on the lower spring retainer I33 is a compression type of coil spring I35 which extends upwardly and surrounds at its upper end an adjusting screw I36 provided with an upper spring retainer I31 which is threaded thereon which receives the upper end of the spring I35. This upper spring retainer I31 is prevented from turning by a projection which extends into a slot provided in the upper vertical portion of the U- shaped bracket I20. The adjusting screw I36 is provided with a flange I38 at its upper end which transmits the thrust of the spring to the U-shaped bracket I20. The upper end of the adjusting screw I36 is provided with a serrated disc I39 which is adapted to receive a key or the control knob 52 or a similar knob in order' to turn the adjusting screw I36 which may be provided with means to limit its free rotation to one revolution. In order to strengthen the U-shaped bracket, a threaded pin I40. is provided with extends from the upper portion of the U-shaped bracket to the lower portion of the bracket in order to prevent the spreading of the extremities of the bracket I20.

In order to control the movement of the bellows follower I provide a floating type of snap acting mechanism. At the free end of thebellows follower I32 there is fastened a block I42, better shown in Fig. 13, which is engaged on either side by a conical pointed pin I43. These pins I43 engage recesses in the arms I44 which are pivoted at their ends to the U-shaped bracket I20 at the rear and to an extension I45 therefrom at the front; These arms I44 are pulled together by a spring means which includes a screw I46 extending inwardly fromone of the arms and having a plate I41 threaded thereon which supports one .end of a compression type coil spring I46 surrounding the screw I46. The other end of the spring I48 bears against the yoke I49 which extends through a slot in the other of the arms and is fastened by a cotter pin I50. With this ar-.

rangement a toggle mechanism formed by the conical points I43, the arm I44, and the spring I48 floats upon the pivot pins II and in this way is enabled to move laterally to take care of any misalignment between it and the bellows follower without substantially afiecting the action of the armature arm 61 to open circuit position regard-' less of the pressure within the bellows 32. This is permitted by the spring controlled slotted link connection 60. This high pressure cut-out therefore prevents the operation of the refrigerating apparatus under high pressure conditions when it would be dangerous to operate the system.

The U-shaped brackets 40 and I20 are provided with laterally projecting pairs of ears which are employed to fasten the pressure responsive means and the high pressure cut-out assemblies to the rear wallof the control housing I66 provided with the electrical inlet and outlet connections I61 and I 68.

If desired, the high pressure cut-out mechanism may be omitted when such is not necessary to protect the apparatus. The overload mechanism may also be omitted if unnecessary. The adjusting screw mechanism for the high pressure cut-out and the temperature and pressure responsive switch means permit a great range of a setting of the control mechanism which is readily effected.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Switch means including means for opening and closing an electric circuit, said means including overload means responsive to a predetermined flow of electric energy through the circuitfor circuit open during the resetting of the overload means.

2. Switch means including means for opening and closing an electric circuit, said means including overload means responsive to a predetermined flow of electric energy through the circuit for opening'the circuit, means for resetting said overload means, said resetting means including a floating lever, means for applying a force to the lever, means contacting with the lever and operated by the reaction of the lever for resetting the overload means, means contacting the floating lever and operated by the, reaction of the floating lever for holding-open the electric circuit during the resetting of the overload means.

3. An overload means including heating means energized by the flowof electric energy, thermal responsive latch means influenced by the heating means for preventing the flow of electric energy under predetermined conditions, said thermal means including heat absorbing means adapted to change its state for delaying the operation of the thermal means.

4. An overload means including heating means energized by the flow of electric energy, thermal responsive latch means influenced by the heating means for preventing the flow of electric energy under predetermined conditions, said thermal means including heat absorbing means in the form of a fusible material for delaying the operation of the thermal means. I

5. An overload means including heating means energized by the flow of electric energy, a thermal fusible latch means influenced by the heating means for preventing the flow of electric energy under predetermined conditions, said thermal means including heat absorbing means in the form of a fusible material for delaying operation of the thermal means.

6. An overload means including heating means energized by the flow of electric energy, a fusible latch means influenced by the heating means for preventing the flow of electric energy under predetermined conditions, said fusible latch means including heat absorbing means in the form of a material fusible at a lower temperature than the fusible latch means for delaying operation of the thermal means.

'7. A switch means including a bellows, a bellows follower, an armature arm carrying a switch contact, a magnet cooperating with the armature arm, and a link having a spring controlled slotted connection for connecting the bellows follower and the armature arm, said spring 'controlled slotted connection comprising means riding in the slot and a spring for resiliently holding said means in one end of the slot.

8. A switch means including a bellows, a bellows follower, an armature arm carrying a switch contact, a magnet cooperating with the armature arm, and a link having a spring controlled slotted connection for connecting the bellows follower and the armature arm and having an adjusting means cooperating with the spring controlled slotted connection for varying the differential of the switch, said spring controlled slotted connection comprising means riding in the slot and a spring for resiliently holding said means in one end of theslot.

9. A control for a medium to be transmitted including an expansible power element capable of moving in a predetermined path, said expansible member being provided with a follower movable in a predetermined path, a floating'snap acting mechanism operably connected to the follower for controlling its movement in its predetermined path, a supporting means for said power member, said floating snap acting mechanism including a plurality of links pivotally connected to the supporting means and extending substantially parallel to the predetermined path of said follower, a set of toggle links pivotally connecting said plurality of links with the follower, a spring means for applying a resilient force to urge said plurality of links toward each other, and means connected to the follower for controlling the transmission of the medium.

10. A control for a medium to be transmitted including an expansible power member, said expansible power member being provided with a follower movable in a predetermined path, a supporting means for said power member, a pair of spaced links pivotally connected at one end to the supporting means and extending generally in the same direction as the predetermined path of the follower, a set of toggle links pivotally connecting the free end of said pair of links with the follower, said set of toggle links extending generally transversely to the path of movement of said follower, a spring means for applying a resilient force to urge said pair of links toward each'other, and means connected to the follower for controlling the transmission of the medium,

11. A switch including a set of switch contacts, an expansible power member, said expansible power member being provided with a follower movable in a predetermined path, a mechanical snap acting means connected to the follower for controlling the movement of the follower, said follower being provided with positive means providing a positive connection with one of the con tacts for positively operating the set of switch contacts.

12. A switch including a set of switch contacts, an expansible-power member, said expansible power member being provided with a follower movable in a predetermined path, a mechanical snap acting means connected to the follower for controlling the movement of the follower, said follower being provided with positive means providing a positive connection with one of the contacts for positively operating the set of switch contacts, a second expansible power member, said second member being provided with means for operating said set of switch contacts independently of the first mentioned power member and follower.

13. In combination, a switch means for controlling the flow of electric energy, means for opening said switch means, a thermal fusible latch means incorporating a fusible material holding a latch means for preventing the operation of said switch opening means, said thermal means including heat absorbing means in the form of a second material fusible at a lower temperature than the fusible latch for delaying the melting of the fusible material holding the latch means.

GEORGE C. PEARCE. 

